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Marine Depot Elite OverFlow Box w/ Holesaw Drill Bit - Large


Item #: MD5503

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Ready to upgrade your filtration? The Elite Overflow Box will open up a whole new world of filtration for your glass or acrylic aquarium.

The Marine Depot Elite Overflow Box is a high quality and economical overflow box that allows you to easily add a sump, refugium or wet/dry filter to your aquarium filtration system. These overflow boxes allow you to skim water from the surface of the aquarium and deliver it to your external filter without the need of expensive modifications to your aquarium.

The Elite Overflow is a slim black box minimalist design, allowing more room in the aquarium for aquascaping and swim room for your livestock.  The Elite will also effectively transport water to your sump with as little noise as possible.

This DIY (Do-It-Yourself) project is a plug and play overflow system with a simple installation procedure; however, we recommend that any drilling and installation be performed by a professional maintenance servicer.


  • (1) Black Wetside Box 
  • (1) Clear Dryside Box
  • (1) Template
  • (1) White Safety PVC
  • (1) Holesaw (60mm Diamond Coated Holesaw)
  • (2) 1.5" Bulkhead
  • (2) 1" Bulkhead for Small & Medium Elite Models
  • (3) 1" Bulkhead for Large Elite Models
  • (1) Black Cover Lid


  • Rated for aquariums up to 200 gallons
  • Internal Dimensions: 12"L x 1.25"W x 6"H
  • External Dimensions: 12"L x 3"W x 6"H
  • Suitable for tanks up to 5/8" thick


Aquarium Rating Internal Box
Dimensions (LxWxH)
External Box
Dimensions (LxWxH)
Drain Bulkheads
(Count x Size)

Elite Small

up to 90 gallons 6" x 1.25" x 6" 6" x 3" x 6"2 x 1"

Elite Medium

up to 150 gallons 8" x 1.25" x 6" 8" x 3" x 6"2 x 1"

Elite Large

up to 200 gallons 12" x 1.25" x 6" 12" x 3" x 6"3 x 1"

Manufacturer information

Marine Depot was started in 1998 by a self-professed reef geek and pre-med student Ken Wong. Ken envisioned a one-stop shop where customers could find everything they needed, from technical product specifications, reef aquarium information, expert advice on the hobby and friendly one-on-one customer support. Having grown from a one-man crew to being one of the world’s largest suppliers of reef and marine aquarium products, this very core philosophy still lives strong in the Marine Depot culture 20 years later.

4 Stars


Reviewed on
March 01, 2021

Yes, I would recommend this.

Very Good Design, could use more directions

Pros: well built, hole saw worked well. looks sharp!

Cons: needs detailed directions shipped with unit

Solid construction, Hole bit worked easily (first time drilling glass). looks super sharp and disappears on black glass.
- Needs directions. The gasket placement is not intuitive. Online info always says "Gaskets go on water side" , this is not the case for this overflow. The gaskets go on the OUTSIDE of the tank and connect to the drain box. I had to search marine depot site for instructions to stop initial leak. Easy solve, just ship with directions!

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Reviewed on
October 23, 2020

Yes, I would recommend this.

Great overflow box

Pros: Great quality and material

Cons: Needs an extra set of gaskets

I recently took on the challenge of drilling my first tank and I picked this overflow box. Everything that came on the package was well packed and it arrived on time. I installed this and the only reason. Why I give 4 stars instead of 5 its because it definitely needs 2 more gaskets cause it does cause a small leak but I fixed it with some rubber material I had laying around. Second it would be much better if it comes with the overflow connections (primary, secondary and emergency piping) beside that it is a great sturdy box.

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Reviewed on
June 08, 2020

Yes, I would recommend this.

Elite Overflow

Pros: Seems to be great quality

Cons: I can see here cleaning the weirs will be a challenge. I would have been happier if the over flow came with some documentation, but there is none and to find any installation instruction for this overflow online- well good luck. and finally I will have to order a second set of rubber gaskets- I would like to have gaskets on either side of the glass.

Over all I like the price point and like the quality of the overflow. There is room however for improvement. Include warranty information, instructions and a invoice. . Improve the design by including a removable weir on the inside of the tank for cleaning. and include two sets of rubber gaskets to ensure a full seal. All in all I am happy with the over flow and its performance

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Reviewed on
May 17, 2020

Yes, I would recommend this.

Awesome design wish there was guidance

Pros: Easy to use

Cons: No idea where to properly put rubber washers

This is my first reef tank/sump set up and this overflow box was perfect for converting my old freshwater tank over. Hole saw was super easy and got clean cuts. I wish there was some guidance on how to set up the box so that I won’t have any worry about leaks (rubber washer locations).

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Reviewed on
May 01, 2020

Yes, I would recommend this.

Elite overflow

Great Product

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Reviewed on
October 14, 2019

Yes, I would recommend this.

Used on rimmed tank

Pros: Flows well. Lids are a plus

Cons: Had to cut plastic rim but that was planned already

I did a little research before I bought the overflow. My tank is rimmed so I had to cut a section of it off to make the overflow fit. It works perfectly now. The drill bit cut through the thick glass of my 60 gal pretty well also.

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